Section 105.639 - Disclaimer by appointee, object or taker in default of exercise of power of appointment(1) A disclaimer of an interest in property by an appointee of a power of appointment takes effect as of the time the instrument by which the holder exercises the power becomes irrevocable.(2) A disclaimer of an interest in property by a person who is an object of an exercise of a power of appointment, or by a person who is a taker in default of an exercise of a power of appointment, takes effect as of the time the instrument creating the power becomes irrevocable.